A Thermal Imaging Instrument with Uncooled Detectors

In this proposed work, we will perform an instrument concept study for sustainable thermal imaging over land with uncooled detectors. We will define the science and instrument requirements and we will evaluate three different uncooled detector technologies, which have been conceptualized by our team (and are presently at low-TRL). We will also build-up and demonstrate the materials characterization infrastructure required for progressing the TRL of a chosen uncooled detector technology.

The National Research Council's Committee on Implementation of a Sustained Land Imaging Program has identified the inclusion of a thermal imager as critical for both current and future land imaging missions. Such an imaging instrument operating in two bands located at approximately 11 and 12 microns (for example, in Landsat 8, and also Landsat 9 when launched) will provide essential information for furthering our hydrologic understanding at scales of human influence, and produce field-scale moisture information through accurate retrievals of evapotranspiration (ET). Landsat 9 is slated to recycle the TIRS-2 instrument launched with Landsat 8 that uses cooled quantum well infrared photodetectors (QWIPs) operating at ~43-65 K temperature, hence requiring expensive and massive cryocooler technology to achieve its required spectral and spatial accuracies (Fig. 1).

In contrast, we aim to conceptualize and develop a thermal imaging instrument which leverages recent and imminent technology advances in uncooled detectors. Such detector technology will offer the benefit of greatly reduced instrument cost, mass, and power at the expense of some acceptable loss in detector sensitivity. It would also allow a thermal imaging instrument to be fielded on board a low-cost platform, e.g., a CubeSat. In addition, it would enable capitalizing on the greater number of launch opportunities available for launch vehicles like the Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA).